Diseases Threatening CT's Mammals

Links are provided if you wish to learn more about a disease.


  • Fatal viral disease primarily found in bats and wild carnivores, such as raccoons, skunks, and foxes

  • Raccoon rabies strain is only terrestrial strain of rabies in CT

  • Found in saliva, transmitted primarily through a bite

    • Can also spread when saliva or central nervous system tissue (brain, spinal cord) enters an open wound or mucous membranes (eyes/nose/mouth)

  • Signs

    • Unprovoked aggression OR unusually friendly

    • Disorientated, impaired movement, difficulty walking

    • Unusual vocalizations

    • Hyper-salivation




  • Raccoons are primary carriers of the parasitic nematode Baylisascaris procyonis

    • Not affected, but dangerous to other mammals that ingest or come into contact with infected feces

  • Can cause intestinal blockage

  • If eggs penetrate the small intestine, can migrate through body, where the eggs hatch and the larvae migrate to the brain, eyes and other organs

    • Serious eye disease or central nervous system infection can cause death or paralysis depending on the location in the body and number of worms  

    • Very rare!



  • Feline Distemper:

    • Caused by parvovirus

    • Affects felines such as the bobcat and lynx (and domestic cat) as well as raccoons, weasels, and skunks

    • Attacks all rapidly dividing cells such as bone marrow

    • Signs:

      • High fever followed by depression, vomiting, anorexia, and diarrhea

  • Canine Distemper:

    • Caused by a paramyxovirus

      • HIGHLY contagious, spreads in many ways

    • Affects same animals except instead of the felines, affects canines such as the wolf, coyote, and fox (and domestic dog)

    • Attacks respiratory, nervous, and gastrointestinal systems

    • Signs:

      • Very similar to rabies: abnormal behavior, apparent lack of fear

      • Nasal discharge, crusty eyes

      • Diarrhea, vomiting leading to weakness, emancipation

      • Labored breathing

Sarcoptic Mange

  • Caused by microscopic Sarcoptes scabiei mites that burrow in skin

  • Sometimes deadly to foxes and coyotes, especially in the wintertime

    • Can be passed to domestic dogs and humans!

  • Signs:

    • Cracked skin, encrusted with scabs

    • Intensive scratching

    • Losing weight and hair


White-Nose Syndrome

  • Caused by Pseudogymnoascus destructans fungus

  • Spreads easily among closely hibernating colonies

  • Signs:

    • White fungus on muzzle or wings

    • Act strangely during cold winter months, including flying outside in the day and clustering near the entrances of hibernacula (caves and mines where bats hibernate)

  • Increases frequency of arousal from torpor and accelerates depletion of fat reserves, leading to starvation

WNS is estimated to have killed more than 6 million bats in the Northeast and Canada since its first appearance in New York in 2006.  In some sites, 90 to 100 percent of bats have died.

Chronic Wasting Disease

  • CWD is a transmissible spongiform encephalopathy (TSE) of mule deer, white-tailed deer, elk, and moose

    • (Generally) only white-tailed deer are found in CT

    • TSE is a neurodegenerative disease caused by prions (disease-causing form of protein)

    • Spongiform meaning it causes sponge-like holes in brain tissue! Always fatal!

  • Can spread through direct contact or indirectly through surfaces where disease is present

    • Commonly through feces and saliva

  • Signs:

    • Advanced stages = staggering, poor posture, droopy ears and head (see picture)

    • Very late stages = emaciated

Diseases Threatening CT's Mammals